Cameras are available in sizes and types from smart phones up to view camera. I'm going to limit this to digital cameras that are dedicated cameras, so no cell phones. On the upper end, medium format is as far as I'll go.

I see two general areas of Fixed Lens Cameras (FLC's). The smaller, less expensive, "snapshot" cameras which really do merit the appelation "point and shoot" and the upscale enthusiast models which I think of as FLC's. I find it hard to think of an RX1 or RX10 or G1X as a point and shoot - they are clearly much more serious than that and deserve a more serious title.

Then there is a wide range of Interchangeable Lens Cameras (ILC's for short). Ranging from the Pentax 10 with a 1/2.3" sensor (the newer 07 has a 1/1.7" sensor) up to a Pentax 645D medium format. Within the ILC's we have DSLR's and Mirrorless ILC's. By the way, all FLC's are mirrorless. The SLT's and earlier pelicle mirror cameras sit in a middle ground.

I could break DSLR's down further; but the pro's and con's are pretty much the same. One characterisitic that all the ILC's share is that the lens projects further for a given focal length and sensor size since there is no room to have it collapse into the body. And there's also a weight and cost penalty to make the lenses interchangeable.

The strengths of the FLC's lie in cost, live view, less chance of dust entering the body, and perhaps size and weight. The rear LCD or EVF has the advantage of no parallax since you're seeing what the sensor sees. The weakness is the fixed (non-interchangeable) lens, the necessity to use an electronic display to see through the lens, parallax with any optical finder, and latency with the electronic displays.

The strengths of the DSLR lie in the reflex finder as you are seeing through the lens with no latency and no parallax, and the interchangeable lenses. You can build a fixed lens DSLR; but I am not aware of any that are currently in production. Another strength is the use of phase detect AF which is better for focus tracking on moving subjects, and so the DSLR tends to be better for sports action. The weaknesses are the phase detect AF which is an "open loop" control system and can have errors in focus accuracy. If the camera has AF micro adjust, it can be tuned out. Phase detect has also been slower for live view; but a lot of work on sensors is being done to correct that. Another weakness is the "mirror slap" noise which is distracting to others around the camera, and can also jiggle the camera causing mild blur. The mirror can be locked up, but that means no view through the lens, so it's strictly for tripod mounted cameras. Further,there is time needed for the mirror to flip up while the picture is taken. Mirror time is a kind of delay in the taking of the shot. It occurs after the shutter button is depressed; but it still means the image taken is a later version of what you saw when you pressed the button. The delay is on the order of 50-100 milliseconds.

Mirrorless ILC's have been around for a good while - think of Leica and Contax models. The digital era models eliminate the mirror and are continuously in live view mode. That gets rid of mirror slap and its noise and vibration. It also means that contrast detect AF is used. They also (like many FLC's) can show you the effect of white balance changes and exposure compensation. Their electronic displays can also be very rich in information displayed. With no mirrors they are mechanically simpler and can have shorter back distances from lens to sensor, making the body thinner. And since they use contrast detect AF, they close the loop on focus and have dead accurate focus. The downsides are the latency in the displays. Latency in the display means that what you are seeing in the electronic display occurred in the past; so the image taken will be a later version of what you saw in the display. Latencies are getting much shorter and have dropped from 250 milliseconds 10 years ago to under 25 milliseconds in the best of today's cameras. Also, using contrast detect AF, they are not as good for tracking motion. In addition, some models show a sensitivity to "shutter shock" with some lenses - caused by the first curtain of the focal plane shutter slamming against its stops. Use of an electronic first curtain fixes that; but not all cameras have that capability, and use of an all electronic shutter can cause distortions in fast moving subjects. I do expect that to go away in the next generation.

The SLT's, are the digital equivalent of the pellicle mirror cameras from the film era. They have a partially reflective mirror that doesn't move. About 70% of the light goes through the mirror to the sensor, and 30% is reflected to a phase detect AF sensor. The optical finder of a DSLR is replaced by an EVF. Back distance is typical of a DSLR, so the body thickness is DSLR-like. The strengths of an SLT lie in the lack of mirror slap vibration and noise, the high speed that bursts can have without the mirror to move, and the continuous live view combined with phase detect AF. The downside is the loss of 1/3 stop of light, and the loss of the optical view through the lens of a true DSLR. Use of an EVF also means some latency; although this is balanced by no mirror time. The pellicle mirror is also fragile and hard to clean. Like a true DSLR, the phase detect AF can have errors in focus, which can be tuned out if the camera has AF micro adjust.

Bottom line here is that all the types have compromises in design and as a result they all have strengths and weaknesses. The trick is to pick the type that has the fewest compromises that will affect your shooting style and subjects.

Why did I take the time to post this? Because I'm tired of the fan boys arguing vehemently that their choice is the best and running down the others.